The Scientific/Administrative Leadership Core provides the scientific, managerial, and coordinating structure to ensure the efficient and effective functioning of the program project. The Scientific/Administrative Core includes experienced research administrators, a set of external scientific advisors, and an Executive Steering Committee that provides scientific integration, quality control, and oversight across projects and cores. Our specific aims fall under three broad domains: scientific leadership, mentoring, and administration. Our scientific leadership aims include: 1) providing overall scientific leadership to the program project; 2) providing an intellectual environment that will generate a collaborative program of multidisciplinary research to address important issues about adolescent and young adult tobacco use, including helping to plan overlapping analyses across projects; 3) providing support for and coordination of the research activities across projects and cores; 4) maintaining policies and procedures for the program project (e.g., publication and presentation policies, authorship and collaborative policies); and 5) coordinating and promoting dissemination of research findings. Our mentoring aim includes providing mentoring and career development opportunities (e.g., peer review publication authorship, national meeting presentations, dissertation projects) for graduate students, post-doctoral fellows and junior faculty. Our administrative aims include: 1) providing overall administrative leadership and support for the program project; 2) maintaining financial oversight of the entire program project; and 3) coordinating all networking between projects, cores, and Institutions to ensure efficient operations and timely communications, including the maintenance of communication vehicles and structures (e.g., password protected web sites for sharing of documents, information across projects, cores, and institutions). Thus, this core plays an essential role in this program project by serving as the coordinating center of the group of investigators and integrating all activities and scientific findings. This type of integration is likely to lead to greater progress in the field.